base: remove unused imports

examples/demo/kivycatalog/kivycatalog.kv

@@ -137,11 +137,11 @@
         TextInput:
             id:info_lbl
             readonly: True
-            font_size: 11
+            font_size: '11sp'
             background_color: (0, 0, 0, 1)
             foreground_color: (1, 1, 1, 1)
             opacity:0
             size_hint: 1, None
             text_size: self.size
             height: '150pt'
-            top: 0
+            top: 0

kivy/base.py

@@ -15,12 +15,10 @@ __all__ = (
     'stopTouchApp',
 )
 
-from os import environ
 from kivy.config import Config
 from kivy.logger import Logger
 from kivy.clock import Clock
 from kivy.event import EventDispatcher
-from kivy.utils import platform, reify
 
 # private vars
 EventLoop = None